Hello!I was watching The Avengers (TV show). Iron Man has this blue circular thing on his chest. He always has it on, even if he is not wearing is suit. Does anyone know why he needs that thing, what it is, and what it does?Thanks!

It is a power supply. Something like cold fusion or some other mystical technology never seem before! It is used to power a magnet to keep the shrapnel away from his heart. Then, was made bigger to power the suit.

The basic thing is he was demoing a weapon in Afghanistan, and was in a convoy that was struck by an roadside bomb, then attacked with his own weapons, a bomb blew up at point blank range and nearly killed him, bits of sharpnel remained in his body, and a Afghani citizen put a electromagnet in him to pull the shrapnel away from his heart, as it would kill him if it reached it, but it was powered by a huge lead acid battery, while in a cave held prisoner he built the Arc Reactor to power the magnet, then built the Iron Man suit prototype, which was basically a suit powered by the Arc Reactor with flame throwers and a turret etc...

I actually assume he eventually DID remove it, but by then it was powering the suit... but then why not place it ON the suit... In the cave he obviously couldn't because the only supplies they had were rudimentary, possibly "too close to the heart/too much of a risk"